feat(push_notification_device): implement read operation and update permissions

- Add read operation for push_notification_device in DataOperationRegistry
- Update getCollectionPermission to unsupported for better security
- Change getItemPermission to adminOnly to restrict unauthorized access

Author: fulleni

lib/src/registry/data_operation_registry.dart

@@ -125,6 +125,9 @@ class DataOperationRegistry {
       'in_app_notification': (c, id) => c
           .read<DataRepository<InAppNotification>>()
           .read(id: id, userId: null),
+      'push_notification_device': (c, id) => c
+          .read<DataRepository<PushNotificationDevice>>()
+          .read(id: id, userId: null),
     });
 
     // --- Register "Read All" Readers ---

lib/src/registry/model_registry.dart

@@ -429,14 +429,12 @@ final modelRegistry = <String, ModelConfig<dynamic>>{
     fromJson: PushNotificationDevice.fromJson,
     getId: (d) => d.id,
     getOwnerId: (dynamic item) => (item as PushNotificationDevice).userId,
-    // Required by the ownership check middelware used by the deletePermission.
     getCollectionPermission: const ModelActionPermission(
-      type: RequiredPermissionType.adminOnly,
+      type: RequiredPermissionType.unsupported,
     ),
-    // Item GET is not supported for this model. A client registers a device
-    // and then forgets about it until it needs to be deleted.
+    // Required by the ownership check middelware
     getItemPermission: const ModelActionPermission(
-      type: RequiredPermissionType.unsupported,
+      type: RequiredPermissionType.adminOnly,
     ),
     // POST is allowed for any authenticated user to register their own device.
     // A custom check within the DataOperationRegistry's creator function will